This invention relates to novel thiophene or furan herbicides and their use as agricultural chemicals. In particular, they are useful as pre- and post-emergence herbicides and as plant growth regulants. Certain compounds within the scope of the instant invention have shown crop selectivity and in particular have shown selectivity toward corn.
Levitt U.S. Pat. No. 4,169,719 discloses herbicidal thiophene and furan sulfonylureas such as: ##STR1## wherein
R.sub.8 is H, Cl, Br or CH.sub.3 ;
R.sub.9 is H, Cl, Br or CH.sub.3 ;
R.sub.10 is H, Cl, Br or CH.sub.3 ;
X is H, Cl, Br, CH.sub.3, C.sub.2 H.sub.5, C.sub.1 -C.sub.3 alkoxy, CF.sub.3, SCH.sub.3 or CH.sub.2 OCH.sub.3 ;
Z is CH.sub.3 or OCH.sub.3 ; and
Q is sulfur or oxygen.
Levitt U.S. Pat. No. 4,127,405 discloses herbicidal thiophene and furan sulfonylureas such as, ##STR2## wherein R.sub.8, R.sub.9, R.sub.10, Q, X and Z are defined as above.
U.S. Ser. No. 153,279 now abandoned discloses herbicidal thiophene sulfonylureas such as, ##STR3## wherein
A is ##STR4##
R is C.sub.1 -C.sub.4 alkyl, NO.sub.2, Cl, Br or SO.sub.2 NR.sub.1 R.sub.2 ; and
R.sub.1 and R.sub.2 are independently C.sub.1 -C.sub.3 alkyl.
U.S. Ser. No. 196,267 now abandoned discloses herbicidal thiophene sulfonylureas such as, ##STR5## wherein
A.sup.1 is H, Cl, Br, C.sub.1 -C.sub.4 alkyl, OCH.sub.3, NO.sub.2 or CF.sub.3 ;
A is ##STR6## and;
B is ##STR7##
R.sub.4 is H or CH.sub.3 ;
R.sub.5 is H, CH.sub.3 or OCH.sub.3 ; and
R.sub.1 is ##STR8##
J. Drug. Res. 6, 123 (1974) discloses antidiabetic thiophene sulfonylthioureas such as, ##STR9## where R is pyridyl.
The presence of undesired vegetation causes substantial damage to useful crops, especially agricultural products that satisfy man's basic food needs, such as soybeans, barley, wheat, and the like. The current population explosion and concomitant world food shortage demand improvements in the efficiency of producing these crops. Prevention or minimizing the loss of a portion of valuable crops by killing, or inhibiting the growth of undesired vegetation is one way of improving this efficiency.
A wide variety of materials useful for killing, or inhibiting (controlling) the growth of undesired vegetation is available; such materials are commonly referred to as herbicides. The need exists, however, for still more effective herbicides that destroy or retard weeds without causing significant damage to useful crops.